On Sunday, October 30, 1897, Abbott delivered an address in New York at the funeral of economist, Henry George, [3] aptly titled, "Henry George: A Remembrance".[4]

Abbott's opinions differed from those of Beecher. Abbott was a constant advocate of social reform, and was an advocate of Theodore Roosevelt's progressivism for almost 20 years. He would later adopt a pronouncedly liberal theology. He was also a pronounced ChristianEvolutionist.[5] In two of his books, The Evolution of Christianity and The Theology of an Evolutionist, Abbott applied the concept of evolution in a Christian theological perspective. Although he himself objected to being called an advocate of Darwinism, he was an optimistic advocate of evolution who thought that "what Jesus saw, humanity is becoming."